When you first switch your computer and monitor on, your screen might look something like this, in the image below .
This is the Windows XP Desktop. There are a number of things to notice about the Desktop. First, all those little pictures on top of the big picture. (Your screen may well be nice and colorful). There are 4 in the image above. The pictures are called icons.
To get some practice with using your mouse, click on each of your Desktop icons. (If you have only one icon, the Recycle Bin, then practice with that for the time being. We'll see how to add shortcuts soon.) Click on them with your Left mouse button, a Single Click. You should notice that the icons change color, usually blue. When they do change color, the icon is said to be selected.
Now click on any of your icons with the Right mouse button, again a Single
Click. What happens now?
You should see a menu popping up with a list of items on it. The menu pops up because of that Right Click - the Right click is usually a shortcut click. Each icon on your Desktop has a shortcut associated with it. Indeed, the icons themselves are shortcuts. Each picture is associated with a program on your computer. When you clicked an icon with your left mouse button, the only thing that happened was that it turned a different color. You had selected it by clicking the icon with your left mouse button.
Now try to double click each icon with the Left mouse button and see what happens. You should find that some sort of software, or program is launched.
So the desktop icons are shortcuts to your programs. That's why they are there - so that you can get at your programs with a Double Click of your left mouse button.